In silver halide photographic light-sensitive materials, techniques wherein a photographically useful group is released as a function of development, have long been known. Among them, in particular, the technique of releasing a photographically useful group through a coupling reaction of a coupler with a color-developing agent is practically used for, for example, color negative films that use DIR couplers. This technique is widely used for the purpose of improving the graininess, sharpness, and color reproduction of images, and that technique has been known as a quite important technique.
In recent years, for the purposes of making the development processing rapid and reducing the influence of processing waste solutions on the earth's environment, a method is suggested wherein a developing solution is not used; rather a color-developing agent is built in a light-sensitive material, and the light-sensitive material is subjected to the so-called activator process, wherein it is processed with a processing solution that does not contain a developing agent. Para-phenylenediamine derivatives widely used as a color-developing agent are an important developing agent in that their oxidation products have chemical structures that cause coupling reaction with couplers having a photographically useful group bonded at the coupling site, to release the said photographically useful group. However, since para-phenylenediamine derivatives have extremely low stability of oxidation resistance, and it is difficult to build them into light-sensitive materials stably, the intended purpose cannot be achieved in the above activator process. To overcome this problem, for examples, as described in JP-A-5-257225 ("JP-A" means unexamined published Japanese patent application), the so-called precursor means is suggested, wherein a para-phenylenediamine derivative is built, in a stable form, in a light-sensitive material, and it is activated during development processing. However, it is difficult to simultaneously make the precursor itself stable and to allow the precursor to be converted to the intended product quickly during processing.
As a color-developing agent that can be advantageously built in, a sulfonylhydrazine derivative described in U.S. Pat. No. 5,284,739 is known. Although this color-developing agent has very high stability of oxidation resistance and it can be built in a light-sensitive material, this color-developing agent is not practically used to release a photographically useful group.
Thus, a practical technique, wherein a photographically useful group is released as a function of development of a silver halide, through use of a combination of a color-developing agent that can be built in with a coupler, is not yet known, and there is a strong need in the art for such a technique.
On the other hand, in color photographic light-sensitive materials, when the photographic material is exposed to light image-wise and then subjected to color development, the oxidized color developing agent and couplers are reacted, and an image of dyes is formed. In this system, color reproduction by the subtractive color process is used, and, to reproduce blue, green, and red colors, dye images are formed that are yellow, magenta, and cyan in color, respectively complementary to blue, green, and red.
Color development is accomplished by immersing the light-exposed color photographic light-sensitive material in an aqueous alkali solution in which a color-developing agent is dissolved (a developing solution). However, the color-developing agent in an aqueous alkali solution is unstable and liable to deteriorate with a lapse of time, and there is the problem that the developing solution must be replenished frequently in order to retain stable developing performance. Further, used developing solutions containing a color-developing agent are required to be discarded, and this, together with the above frequent replenishment, creates a serious problem regarding the treatment of used developing solutions that are discharged in large volume. Thus, low-replenishment and reduced discharge of developing solutions are strongly demanded.
One effective measure proposed for realizing low-replenishment and reduced discharge of developing solutions is a method wherein an aromatic primary amine developing agent or its precursor is built in a hydrophilic colloid layer of a color photographic material. Examples of the developing agents that can be built in include compounds described, for example, in GB-803 783, U.S. Pat. Nos. 3,342,597, 3,719,492, and 4,060,418, GB-1 069 061, West German Patent No. 1 159 758, JP-B-58-14671 ("JP-B" means examined Japanese patent publication) and 58-14672, and JP-A-57-76543 and 59-81643. However, color photographic materials having these aromatic primary amine developing agents or their precursors built therein have a defect that satisfactory color formation is not attained when they are chromogenically developed. Another effective measure proposed is a method wherein a sulfonylhydrazine-type developing agent is built in a hydrophilic colloid layer of a color photographic material, and examples of the color-developing agent that can be built in include compounds described, for example, in EP-A-545 491 and 565 165. However, even the developing agent mentioned therein cannot attain satisfactory color formation when color-developed; and further, when, for this sulfonylhydrazine-type developing agent, use is made of a two-equivalent coupler, there is the problem that color formation hardly takes place. In comparison with four-equivalent couplers, two-equivalent couplers have the advantages that stain due to couplers can be reduced, and that the activity of the couplers can be easily adjusted by the substituent. Accordingly, there is strong need for a developing agent that, even when built-in, can provide satisfactory color formation when developed, and that also can show good color-formation property in developing an image, even when a two-equivalent coupler is used.
Further, there was the problem that unfavorable color muddiness or rise of density of the white background were occurred, because of the increase of minimum density due to fog at developing process.